This invention relates to a variable air flow oven employing an air directing control device to produce variable air flows under positive pressure in alternating patterns in inverse ratios through jet orifices in opposite side walls of an oven.
In the past, various devices have been employed to conduct heated air over a food product to be processed or cooked in an oven, and most of such devices have required the use of various arrangements to move the food product or the supporting racks in order to provide an even distribution and contact with heated air passing through the oven.
In one type of known system there is a reversible crossflow of heated air whereby static pressure increases on one side of the oven while a relative vacuum is drawn on the other causing the air to flow across a heated area. This method has a severe disadvantage in that the heated air cannot be drawn over a very large distance. Furthermore, it usually required movement of the food product to enable substantially uniform contact of the foods with the heated air.
Other types of mechanical ovens for food processing include revolving trays, travelling trays, rotary racks, and tunnel-conveyor type devices. In all these types of ovens, the temperature is not uniform throughout the cooking area of the oven, and the product must be moved through various heat zones. Ordinarily, heat is introduced into the baking chamber at the bottom or near the bottom of the oven and the product is kept in motion during the baking or processing cycle in order to pass through all temperature zones within the oven to attain the objective of even temperature processing for all the products. The requirement for various mechanical devices to move the product through the oven is a significant disadvantage, but it has been required in attempting to obtain uniform distribution of the heated air.
In contrast, a small home use oven has a very limited volume wherein it is not essential to move the product around in the oven to achieve satisfactory baking. This is entirely due to the very limited capacity of the cooking chamber.
However, in commercial ovens it has been necessary in the past to provide some kind of device to cause movement of the food product within the oven cooking chamber to insure that the product will move through the variable heat zones for uniform distribution and for even baking or processing.